3 files changed, 21 insertions, 3 deletions

diff --git a/kernel/kmod.c b/kernel/kmod.c
index fb326365b694..b086006c59e7 100644
--- a/kernel/kmod.c
+++ b/kernel/kmod.c
@@ -571,6 +571,10 @@ int call_usermodehelper_exec(struct subprocess_info *sub_info, int wait)
         DECLARE_COMPLETION_ONSTACK(done);
         int retval = 0;
 
+        if (!sub_info->path) {
+                call_usermodehelper_freeinfo(sub_info);
+                return -EINVAL;
+        }
         helper_lock();
         if (!khelper_wq || usermodehelper_disabled) {
                 retval = -EBUSY;
diff --git a/kernel/pid.c b/kernel/pid.c
index ebe5e80b10f8..9b9a26698144 100644
--- a/kernel/pid.c
+++ b/kernel/pid.c
@@ -273,6 +273,11 @@ void free_pid(struct pid *pid)
                          */
                         wake_up_process(ns->child_reaper);
                         break;
+                case PIDNS_HASH_ADDING:
+                        /* Handle a fork failure of the first process */
+                        WARN_ON(ns->child_reaper);
+                        ns->nr_hashed = 0;
+                        /* fall through */
                 case 0:
                         schedule_work(&ns->proc_work);
                         break;
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 53cc09ceb0b8..d7d498d8cc4f 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -328,10 +328,19 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
-        if (!force_irqthreads)
-                __do_softirq();
-        else
+        if (!force_irqthreads) {
+                /*
+                 * We can safely execute softirq on the current stack if
+                 * it is the irq stack, because it should be near empty
+                 * at this stage. But we have no way to know if the arch
+                 * calls irq_exit() on the irq stack. So call softirq
+                 * in its own stack to prevent from any overrun on top
+                 * of a potentially deep task stack.
+                 */
+                do_softirq();
+        } else {
                 wakeup_softirqd();
+        }
 }
 
 static inline void tick_irq_exit(void)